1. Field of the invention
This invention relates to a method and apparatus for pipe-end shaping and welding for pipe connections and more particularly to a plurality of pins having a track on one end for forming a template for pipe end shapes. The pins engage the contour of the surface to be cut or welded.
2. Description of the Related Art
In many industrial applications, such as mechanical piping, pressure vessels and steel construction, it is often necessary to join one pipe to another or to other receiving components. The pipe fitting process usually involves shape cutting of the pipe end. The cutting is always done so that the pipe end contour matches the geometry of intersection of the pipe with the other receiving component. The fabrication process may also require beveling the pipe end along the cut line in order to receive the proper welding.
The most commonly used tools for cutting and beveling pipe ends are pipe beveling machines, also known as short saddle machines. Some of the commercially available pipe beveling machines are equipped to receive shape cutting attachments known as guide templates or shape cutting attachments. These metal guide templates allow the user to cut and bevel contoured pipe ends for saddle connections such as T-joints and miter angles. Shape cutting attachments are always of cylindrical shape with one end contoured, and the other end equipped with a set of small bolting brackets. The square end is fitted to the face of the beveling machine, then the torch ruler of a short saddle machine is engaged with the contoured edge of the metal guide. With the torch ignited, the torch arm mechanism is rotated using manual or mechanical devices. A spring tension, exerted on the roller, causes the roller to follow the shaped end of the metal template, duplicating the shape of the pattern.
A pre-fabricated template is used to produce a single specific shape-cut. To cut a pipe end to take a specific contour, a specific corresponding guide template will have to be used. The fabricator can not use a pipe-beveling machine to cut or bevel pipe ends to shape, if the corresponding metal guide template is not available. This drawback limits the fabricator""s options to either shape-cut pipes using a hand held torch or to keep on hand a large number of guide templates. Hand held torch cutting does not yield accurate results and usually requires additional grinding and filing. It is also very difficult to maintain a beveling angle while using a hand held torch. The process of custom making a metal guide template is complicated and involves several steps. The first step involves drawing the unfolded shape of the guide template. The next steps are marking, cutting, rolling and welding a metal sheet. The process of drawing the unfolded shape of the template requires a great deal of knowledge of descriptive geometry methods and manual or CAD drafting. Programmable pipe shape cutters are very expensive and require highly skilled workers to operate. Programmable pipe shape-cutters usually produce a limited number of standard shape cuts corresponding to commonly used pipe connections.
The prior art, involving layout of pipe connection templates, may require both joining components to be brought together and positioned at the desired orientation with respect to each other. That process requires both time and physical effort. The effort involves moving, lifting, and building temporary fixtures to hold both joining components in a specific position. It also requires tedious measuring. The larger the size of the joining components, the greater the amount of physical work involved.
Both manual and CAD drafting methods can be utilized to derive the unfolded shape of the widely used metal guide template, from the pipe connection template however this prior art is considered tedious and time consuming.
The present invention pertains to an apparatus and a method for fabricating pipe connections involving pipe-end shape cutting. It provides a cost-effective system for pipe end universal shape cutting and beveling. In one embodiment of the invention the system 1 consists of three devices referred to as: (a) the universal template, (b) the template adapter and (c) the miter table. The three mentioned devices work together and inter-connect. An aspect of this invention is to allow a cutting torch of a pipe saddle machine to follow a flexible track, cutting and beveling a pipe end for a smooth shape-cut. The flexible track can be secured in place to form any shaped smooth surface guide template. One objective of the present invention is to eliminate the need to keep on hand a large number of pre-fabricated metal guides.
The universal template is generally shown is shown in FIG. 1 as 1A. It comprises a plurality of pins arrayed in a the shape of a cylinder, a pin sleeve with a locking mechanism to hold the pins in place, an adjustable flexible moving track on one end of the pins, and stationary cylindrical sleeve with a mounting flange for attaching a working tool.
The universal template relies on a template adapter, to generate the shape of the track template. The current invention relates to a method of generating the track template for any given pipe end shape-cut, using the template adapter. The template adapter is made of a full array of Z-shaped pins arranged radially to form the shape of a stepped cylinder. One side of the template adapter has a diameter equal to the outer diameter of the pipe, while the other side has a diameter equal to the stationary pipe sleeve of the universal template. As the narrow side of the adapter takes the shape of the connection template, the pins will slide, along the adapter""s wide sleeve and the adapter""s narrow sleeve, allowing the wide side to take the shape of the desired track template. The track template is transferred onto the universal template to be used for shape cutting. The template adapter provides a simple and direct generation of the desired track template. The objective of the template adapter is to eliminate the complex process of deriving and drawing the unfolded shape of a guide template.
The template adapter can be used with a miter table for a precise and quick method of relative positioning of the template adapter with respect to a receiving component or its representative. The miter table provides means for quick relative positioning of the template adapter with respect to a receiving object, allowing the template adapter to generate both connection templates and track templates for miter cuts, concentric, or offset pipe connections.
The template adaptor can be used with a set of lightweight curved plates employed with the system 1 or 1xe2x80x2 for the template generating process. Each curved plate represents a portion of a large pipe or a large diameter shell such as a boiler. Each of the said curved plates is labeled with a size tag showing the nominal or actual diameter of the represented shell. The curved plates are made of plastic or light metal and cover a wide range of pipe and large shell diameters. The objectives of the lightweight plates are to minimize the physical effort involved in the fabrication process, and to generate the connection and track templates without having the two joining components present during that process.
It is an object of the invention to provide a smooth and acurate shape track for cutting, beveling and welding tools to follow to better quality pipe connections.
It is an object of the invention to improve shape transfers from one surface to another.
It is an object of the invention to eliminate trace approximations caused by of pins causing a step function trace.
It is an object of the invention to improve the quality and accuracy of cutting beveling and welding pipe connections.
It is an object of the invention to position offsets of pipes with greater accuracy when connecting the pipes.
It is an object of the invention to eliminate the use of paper templates.
It is an object of the invention to eliminate shape cutting using a hand held torch.
It is an object of the invention to eliminate the need to have multiple sets of metal templates used to cut pipe connections.
It is an object of the invention to eliminate errors introduced by multiple steps of approximations in cutting pipes for pipe connections.
It is an object of the invention to bevel pipes at correct angles for improved fits of pipes in pipe connections.
It is an object of the invention to improve the weld quality of pipe connections to eliminate leaks and reworking of welds.
It is an object of the invention to form templates for and cut complicated pipe ends.
It is an object of the invention to automatically cut pipe ends from a template for (non standard) pipe connections, including connections with the receiving component having an irregular geometry.
It is an object of the invention to prepare pipe connections without having the receiving component present.
It is an object of the invention to produce templates for cutting large sized pipe ends where the pipes from curved plates avoiding having to work with large heavy pipes.
It is an object of the invention to improve the quality of fabrication of pipe connections comprising acute angles or offsets or a combination of both.
It is an object of the invention to increase the productivity of pipe connection layout and fabrication.
It is an object of the invention to use one device to prepare a pipe end by shape cutting, beveling, (or welding), covering a wide range of pipe sizes and connection configurations for both field and shop fabrication.
Other objects, advantages and novel features of the present invention will become apparent from the following description of the preferred embodiments when considered in conjunction with the accompanying drawings.